The efficacy of an antiperspirant salt can be increased, improved and/or sustained for a longer period of time by enhancing the amount of small molecules of the antiperspirant active salt. Typically, when an aluminum or aluminum-zirconium antiperspirant salt is formed, it tends to polymerize into a number of polymeric species. Each polymeric species is correlated with at least one HPLC peak (also referred to as a GPC peak in U.S. Pat. No. 6,066,314). In U.S. Pat. No. 6,066,314, FIGS. 1-6 thereof represent GPC plots of peaks 1, 2, 3, 4, 5 and 6. Peak 1 corresponds to a zirconium polymeric species with peaks 2-6 corresponding to aluminum polymeric species. The area under the curve (AUC) at the position of each peak is proportional to the amount of the corresponding polymeric species.
Without being bound by theory, it is believed that the size of the polymeric species corresponding to peaks 5 and 6 are smaller than the polymeric species corresponding to the other aluminum peaks (i.e., peaks 2-4). Again without being bound by theory, it is believed that the sequence of the peaks corresponds to the size of the corresponding aluminum polymerics so that peak 2 polymer size>peak 3 polymer size>peak 4 polymer size>peak 5 polymer size>peak 6 polymer size.
It is further believed, without being bound by theory, that the antiperspirant efficacy of a given antiperspirant is inversely proportional to the polymer size of the relevant polymeric species. Also without being bound by theory, this is believed to be true because smaller antiperspirant polymeric species can more readily occlude a pore to a degree sufficient to produce the desired antiperspirant effect. In sum, it is believed that smaller species plug-up the sweat pores more readily and more effectively than do the larger species and, therefore, antiperspirants having a higher proportion of the smaller species will be more effective.
This theory is the basis for the discussion of peak ratios described in U.S. Pat. No. 6,066,314 (assigned to the Colgate-Palmolive Co.) and U.S. Pat. No. 6,245,325 (assigned to the Gillette Company). In the '325 patent, there is a discussion of the ratio of the peak 4 AUC/peak 3 AUC. This ratio can be increased by increasing the portion of the smaller peak 4 species and/or decreasing the relative portion of the larger peak 3 species. Thereby, the efficacy of the antiperspirant can be enhanced, increased and/or maintained for a longer period of time. In effect, the effort is to improve the stability of the smaller peak 4 species over that of the larger peak 1, 2, and/or 3 species.
To ascertain whether a particular antiperspirant's efficacy has been improved, a number of ingredients may be added to the antiperspirant and then the peak 4 AUC/peak 3 AUC ratio measured by HPLC or GPC as described in the '314 patent. So, as the peak 4 AUC/peak 3 AUC ratio is increased, the proportion of the desirable smaller peak 4 species is increased relative to the less desirable larger peak 3 species.
This peak 4 AUC/peak 3 AUC ratio is also referred to herein as the peak 4/peak 3 ratio or a “first ratio.” Another peak ratio, i.e., the peak 1 AUC/(peak 2 AUC+peak 3 AUC+peak 4 AUC+peak 5 AUC+peak 6 AUC) ratio is referred to herein as the “second ratio.” Also, because peaks 5 and 6 often appear as a single merged peak at peak 5, this “second ratio” is also sometimes referred to as the peak 1 AUC/(peak 2 AUC+peak 3 AUC+peak 4 AUC+peak 5 AUC) ratio with the understanding that the peak 6 AUC is part of the peak 5 AUC.
Additionally, the “first ratio” is proportional to an 27al NMR peak appearing at 63.5 ppm. Thus, an increase in the “first ratio” and an increase in the intensity of the “27al NMR peak appearing at 63.5 ppm”, each represent what is believed to be an increase in the amount of the peak 4 species relative to the amounts of the other polymeric species of the other 2, 3, 5 and 6 peaks. It should be born in mind that peak 1 corresponds to zirconium species and peaks 2-6 correspond to aluminum species.
While the above-noted theory is believed to be sound, such understanding is made without being bound by theory in the event that the changes measured in the “first ratio”, “second ratio” and the “27al NMR peak appearing at 63.5 ppm” yield a more efficacious antiperspirant product due to some, as yet, unrecognized mechanism.
With the foregoing background being provided, there is a need to provide a more effective antiperspirant product. It is believed that a more effective antiperspirant product can be provided by increasing its “first ratio,” decreasing its “second ratio,” and/or increasing the intensity of the “27al NMR peak appearing at 63.5 ppm.”
It is desirable to provide a more effective antiperspirant. It is also desirable to provide an antiperspirant with an increased “first ratio” and/or a decreased “second ratio.” It is also desirable to provide an antiperspirant having an increased intensity of the “27al NMR peak appearing at 63.5 ppm.”